This invention relates to an image recognizing apparatus, for use in a print inspecting apparatus for inspecting printed states of printed matters, for recognizing images on the printed matters conveyed.
In an image recognizing apparatus for picking up, as image data, images on conveyed to-be-recognized objects (e.g. printed matters), and comparing them with a reference image to identify them, it is necessary to accurately align the reference image with an image on each to-be-recognized object in order to estimate the degree of correspondence therebetween. However, in the image recognizing apparatus, the to-be-recognized object skews or slides while it is conveyed, and different objects to be recognized assume different conveyance states.
In light of the above, it is necessary to accurately detect to-be-recognized objects one by one. In the case of a recognition section incorporated in the conventional print apparatus, a detection method has been proposed, in which detection and positioning are performed with reference to a mark ("+" which is called a "register mark", or a line) printed on a medium together with a to-be-recognized object. Further, where the format of a to-be-recognized object is known as in the case of a document, journal or a driver's license, a horizontal rule in the to-be-recognized object is sometimes used as a reference for positioning.
In addition, Japanese Patent Application KOKAI Publication No. 6-318246 discloses a method used in a case where there is no reference within a to-be-recognized object. Specifically it discloses a method for correcting and positioning an image on the basis of information output from a sensor for detecting the conveyance state of a to-be-recognized object.
As described above, there has been employed a method for printing a positioning reference mark as well as a to-be-recognized object, a method for performing positioning using a horizontal rule within a to-be-recognized object, or a method which uses a sensor for sensing a conveyance state. These methods, however, have disadvantages as described below.
In the method for printing a positioning reference mark as well as a to-be-recognized object, it is necessary to previously print, as well as a to-be-recognized object, a pattern as the reference mark outside the to-be-recognized object. Moreover, it is necessary to provide a cutting mechanism for removing the reference mark pattern after printing.
The method for performing positioning using a horizontal rule within a to-be-recognized object uses a pattern within an object and is therefore free from the aforementioned problem. However, this method cannot be applied to a to-be-recognized object which does not include such a reference horizontal rule.
Furthermore, a method which uses a sensor for sensing a conveyance state requires such a conveyance state sensing sensor in addition to a sensor for picking up an image, which means that the method requires a large scale apparatus.